1. Field of the Invention
The present invention relates to an improved system for alerting operators of aircraft during ground operations that the aircraft is approaching a runway or other designated area.
2. The Prior Art
Within the aviation industry, a serious concern exists regarding the unauthorized entry of aircraft onto airport runways during taxiing operations, which is commonly referred to as a “runway incursion.” This concern has recently been heightened by a number of recent incidents involving “near-misses” occurring when two aircraft have attempted to use the same runway or intersecting runways at the same time, resulting in the potential for a disastrous collision. In another recent incident, a commercial aircraft crashed during takeoff, due to the fact that the pilot had attempted to take off from the wrong runway, which was shorter than the minimum required takeoff distance for the aircraft.
Various systems have been used in the past in order to minimize the potential for runway incursions. A number of “traditional” systems are described in U.S. Pat. No. 6,606,563, which have primarily relied on the pilot and/or air traffic controller to monitor the position of the aircraft relative to airport runways during taxiing operations. These systems have included requiring a pilot to request permission from an air traffic controller before taxiing across a runway, relying on air traffic controllers to visually monitor the movement of aircraft while taxiing, and placing signs and markings on the ground to indicate the position of an aircraft relative to a given runway. However, such systems are not well suited to prevent runway incursions at many of today's larger airports, which include many runways and taxiways where dozens of aircraft may be taxiing, taking off or landing at any given time. Moreover, such systems are less reliable at night or during low-visibility conditions, when the ability of pilots and air traffic controllers to monitor conditions visually is diminished.
U.S. Pat. No. 6,606,563 discloses a system for alerting an operator of a vehicle, such as an aircraft, that the vehicle is approaching or within a zone of awareness, such as a runway. The system includes an electronic database which stores the location of the zone of awareness, a positioning system (e.g., GPS) which determines the location of the aircraft, a processor which calculates the distance between the vehicle location and the zone of awareness, and an alarm that alerts the pilot when the distance is less than a predetermined value. All of these components are located on the aircraft itself, so that the system need not rely on input from outside sources, for example air traffic control systems, in order to warn the pilot of a potential runway incursion.
The storage device of this system comprises a conventional computer memory device (e.g., RAM, CD-ROM, EPROM), in which is stored a database including location information for any desired number of zones of awareness. The zones of awareness may include all or part of a runway, and may additionally include any other area for which an alert would be desirable if approached by an aircraft (e.g., construction zone). The coordinates for each zone of awareness may be determined relative to the surface of the earth, e.g., longitude and latitude.
The alarm function is disclosed as including either audible and/or visual components. The audible alarm may include a synthesized voice warning identifying the name of the runway (e.g., “ENTERING RUNWAY 27”) and/or the location of the aircraft relative to the runway (e.g., “RUNWAY AHEAD”). The visual component of the alarm may include a designation of a feature within the zone of awareness, such as the word “RUNWAY displayed on a screen, an identification of a specific runway (e.g., “RUNWAY 27”) on a screen, and/or other information such as a map of the airport showing the location of various geographical features.
While the alerting system disclosed by U.S. Pat. No. 6,606,563 provides pilots with some notification of potential runway incursions, as described above, that system does not teach the use of a conventional electronic airport chart to display a graphical depiction of the present position of an aircraft, relative to the runway of interest and other geographical features of the airport. Thus, while the pilot may understand that he is approaching a runway, he may not immediately realize where the runway is located relative to his aircraft or which way he should proceed to avoid entering the runway—particularly if he is operating at an airport with which he is unfamiliar. Moreover, if the pilot has entered a runway different from the runway on which the aircraft has been cleared to take off, he may not be cognizant of that fact based solely on an audible warning or a visual designation such as “RUNWAY appearing on a display screen. Accordingly, it would be desirable to combine a warning that the aircraft is approaching a runway, with a visual notification to the pilot identifying precisely where the aircraft is located relative to various geographical features within the airport, at the time of the notification.
Systems for displaying the position of an aircraft on a display device relative to geographical features at an airport, such as runways, taxiways, terminals, etc., are known in the art. Electronic airport charts, such as those provided by Jeppesen Sanderson, Inc. (“Jeppesen”) in association with its JeppView software, are routinely utilized by pilots to obtain a graphical depiction of the position of an aircraft relative to other geographical features of an airport.
Electronic airport charts are typically stored in a computerized database, which is either located on a hard disk drive or a CD-ROM drive connected to an onboard computer system. One such system is the Application Server Unit (ASU) offered by Universal Avionics Systems Corporation (“Universal Avionics). The computer system typically includes a display unit on which the airport charts are displayed, which may comprise either a panel-mounted display unit, such the EFI-890R diagonal flat screen display unit from Universal Avionics, or a portable, standalone display unit, such as the Universal Cockpit Display Terminal (UCDT) from Universal Avionics. Typically, such systems are able to utilize avionics data obtained from the aircraft's flight management system (FMS), including position, heading, track and velocity data, to provide a graphical depiction of the aircraft's present position and heading on the airport chart display.
Alternatively, the database may comprise part of a portable, standalone computer system, such as an electronic flight bag (EFB) system, which may or may not be integrated with the aircraft's avionics systems. One such EFB system is the Universal Cockpit Display (UCD) system, from Universal Avionics, which comprises a Universal Cockpit Display Computer and one or more UCDT display units. Such a system can provide the flight crew with a variety of information such as checklists, airport and aeronautical charts, external video displays, electronic documents and weather data. However, EFB systems, and particularly those systems which are not capable of receiving data from the aircraft's avionics systems, have limited capability of notifying the flight crew of potential runway incursions, as they typically have limited or no capability of obtaining data regarding the aircraft's position and velocity, for display on an airport charts stored within the database.
Standard airport charts, while useful for providing general position information, were previously limited by the fact that positional coordinates on the charts were not indexed to a fixed global reference frame, such as the WGS 84, which is the reference system used by the Global Positioning System (GPS). As a result, such charts were likely to generate significant error between the actual position of the aircraft relative to airport geographical features, as determined by GPS, and the aircraft position displayed on the airport chart, because the positional coordinates on those charts were not based on WGS 84. The difference between the true position of the aircraft and the position displayed on a standard electronic airport chart could potentially total tens or hundreds of meters. Thus, such charts were simply not capable of displaying the position of an aircraft with sufficient accuracy to identify potential runway incursions.
In recent years, providers of airport charts, such as Jeppesen, have solved this problem by providing “geo-referenced” airport charts, in which each coordinate on the chart is indexed to a particular geographical location having a specific latitude and longitude, as determined relative to a fixed global reference frame such as the WGS 84. As a result, a position of an aircraft determined using GPS can be displayed on a geo-referenced airport chart with an accuracy unobtainable using standard, non-geo-referenced airport charts.
However, in order to realize the significant advantages afforded by the use of geo-referenced airport charts, it is important that the system include some method for monitoring and identifying inconsistencies between the source data (which includes both the stored airport geographical feature data as well as dynamic aircraft position and orientation data) and the graphical presentation of that data on the aircraft display device. Without providing such a monitoring feature in association with the use of geo-referenced airport charts, the runway, taxiway, aircraft position or other airport element could be incorrectly drawn on the display, without the pilot being aware of such an error. This could result in either a false notifications of a potential runway incursion, or a failure to notify the pilot of an actual potential runway incursion.
Another system for alerting pilots of potential runway incursions is the surface area movement management (SAMM) software system provided by Aviation Communication & Surveillance Systems (ACSS). The SAMM system provides pilots with warnings of potential runway incursions, by monitoring position signals received from other aircraft engaging in taxiing, takeoff or landing operations at the same airport, such as ADS-B transmissions and mode-S transponders. Based on such information, the SAMM system can provide pilots with a warning if another aircraft enters the same runway during a takeoff operation. For example, is an airplane equipped with SAMM were to start its takeoff roll just as another aircraft equipped with ADS-B or a mode-S transponder taxied onto the active runway, the cockpit display in the SAMM-equipped aircraft would immediately draw a red box around the active runway, highlight the threat aircraft in red, and provide an aural alert.
However, while the SAMM system is capable of warning a pilot of potential incursions by other aircraft onto a runway being used by his aircraft, and highlighting the position of both aircraft on an electronic airport chart, it does not provide the pilot with any notification prior to his own aircraft entering onto the runway in the first place. Thus, a pilot who has entered the wrong runway prior to takeoff would not be provided with a notification of which runway the aircraft has entered, prior to his attempting to take off.
While systems such as those disclosed above are capable of alerting pilots to potential runway incursions under certain circumstances, they each have significant limitations. Thus, it would desirable to provide a system for notifying a pilot that his aircraft is approaching a runway or other geographical feature of interest, while simultaneously identifying the position of the aircraft relative to a geo-referenced airport chart. This would ensure that the pilot was not only made aware that his aircraft would enter a runway if it continues on its current path, but also enable the pilot to immediately assess the location of his aircraft relative to other airport features. This would likewise minimize the possibility of a pilot attempting to take off from the wrong runway, by enabling the pilot to visually confirm from the airport chart display that the aircraft is indeed on the correct runway—particularly at night or during periods of low visibility when runway markings, lights, etc., may be insufficient for that purpose.
It would likewise be desirable to provide a method of notifying a pilot that his aircraft is approaching a runway or other feature of interest, in which the notification includes both a visual notification associated with a geo-referenced airport chart, and an audible notification identifying the runway or feature of interest. Still further, it would be desirable to provide a method of basing the timing of the notifications to the speed of the aircraft. This would ensure that regardless of aircraft speed, the aircraft operator always has sufficient time and distance to respond to an alert.
It would further be desirable to provide such a method which further includes monitoring and notifying the pilot of any errors or inconsistencies between source data (either stored airport data or dynamic aircraft position orientation data) and the graphical presentation of that data on an aircraft display device.